研究目的
Investigating the photoelectric properties of lead-free mixed inorganic perovskite RbGe1-xSnxI3 by changing the metallic ion concentration and position to overcome the shortcomings of large effective masses, wide band gap, and affected photovoltaic performance.
研究成果
The study demonstrates that RbGe1-xSnxI3 perovskites exhibit tunable direct band gaps and improved transport and optical properties by varying the proportions and doping positions of Sn atoms. Specifically, the configuration with Sn atom at the equator plane in RbGe0.50Sn0.50I3 shows superior mobility of electron and optical absorption properties. These findings suggest that modifying metal concentration and position is a viable method to enhance the optoelectronic performance and photovoltaic properties of mixed metal perovskites.
研究不足
The study is theoretical and relies on computational models, which may not fully capture all real-world physical phenomena. The practical application of these findings requires experimental validation to confirm the predicted properties and performance of RbGe1-xSnxI3 perovskites.
1：Experimental Design and Method Selection:
The study employs Density Functional Theory (DFT) to investigate the geometrical, electronic, and optical properties of RbGe1-xSnxI3 with various compositions of metal atoms. The Vienna Ab-Initio Simulation Package (VASP) is used for calculations, applying the projector augmented plane-wave (PAW) method and the generalized gradient approximation (GGA) of the Perdew-Burke-Ernzerhof (PBE) functional. The Heyd-Scuseria-Ernzerhof (HSE06) is also applied to calculate the band gap and analyze the band edge due to the underestimation by PBE.
2：Sample Selection and Data Sources:
The unit cell of perovskite RbGe1-xSnxI3 is modeled by replacing the Ge with Sn atoms in variable ratio (x=0, 0.25, 0.5, 0.75, 1).
3：25, 5, 75, 1).
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: Computational resources from the Changsha Supercomputer Center are utilized.
4：Experimental Procedures and Operational Workflow:
All atomic positions are optimized until the force tolerance on each atom is smaller than 0.02 eV/?. A plane-wave cutoff energy of 400 eV is employed, and a 4×4×3 Monkhorst-Pack grid of reciprocal space integration is used for the mixed metal perovskite. For the calculation of optical properties, the dense k-point mesh is set to 6×6×
5：02 eV/?. A plane-wave cutoff energy of 400 eV is employed, and a 4×4×3 Monkhorst-Pack grid of reciprocal space integration is used for the mixed metal perovskite. For the calculation of optical properties, the dense k-point mesh is set to 6×6×Data Analysis Methods:
4.
5. Data Analysis Methods: The charge carrier effective masses are evaluated by fitting the valence band maximum (VBM) or conduction band minimum (CBM). The optical absorption spectrum is determined by calculating the absorption coefficients.
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